WO2010094875A1

WO2010094875A1 - System and method for controlling the recharging of a battery

Info

Publication number: WO2010094875A1
Application number: PCT/FR2010/050216
Authority: WO
Inventors: Denis Porcellato; Eric Breton
Original assignee: Peugeot Citroën Automobiles SA
Priority date: 2009-02-17
Filing date: 2010-02-09
Publication date: 2010-08-26
Also published as: CN102317103A; EP2398670A1; FR2942358B1; CN102317103B; FR2942358A1

Abstract

The present invention relates to a system for controlling the recharging of a battery that stores electrical power supply energy (5) for an electrical or hybrid vehicle traction system in the immobilized phase. According to the invention, it comprises: - a data interface (1), - an electronic battery control computer (4), this computer being connected in parallel to the battery (5) and to battery recharging means (6, 7), - a vehicle supervisor (3) connecting the data interface (1) to the electronic battery control computer (4) via an intelligent peripherals unit BSI (2), - said electronic battery control computer (4) comprising means of receiving data emitted from the data interface (1) via the vehicle supervisor (3) and the intelligent peripherals unit BSI (2), data processing means for determining a length of time for which the vehicle has been immobilized from this data and determining the time taken to fully charge the battery from the initial battery charge level and means for programming charging setpoints for the charging of the battery (6, 7) as a function of the time of immobilization with respect to the charging time so that the battery reaches the highest level of charge just before it is used so that it remains in a state of low or lowest charge for the longest possible length of time while in storage.

Description

SYSTEM AND METHOD FOR RECHARGING A BATTERY

The present invention relates to a charging management system of an electric power storage battery power supply of an electric or hybrid power train of a vehicle. The invention also relates to an associated recharge management method.

The present invention is intended in particular to increase the life of a battery while reducing the manufacturing cost of such a battery by avoiding its oversizing compared to the specifications for which the vehicle was designed.

One of the current goals with regard to electrochemical storage sources (ESS) is that they can last the life of the vehicle, usually between 10 and 15 years.

There are two types of aging: aging due to its use and calendar aging that corresponds to the intrinsic aging of the battery. The aging of a battery is expressed by the gradual loss of performance in terms of energy and available power. Therefore, the battery must be oversized at the beginning of life so that it can always meet the specifications in terms of energy and end-of-life power. But the battery is an expensive component that must be dimensioned to the fair according to the specifications of the vehicle, to minimize the impact of its cost.

Batteries that are physicochemical components are particularly sensitive to state of charge and temperature. Thus the two main parameters that influence the calendar life and aging due to its use are the state of charge and temperature. The lower the storage or use temperature, the better the service life. Likewise, the lower the state of charge at which the battery is stored or used, the better the service life. Table 1 above illustrates life expectancy data calendar expressed in years for a Lithium battery according to the state of charge compared to its capacity of load for three temperatures 25 ° C, 45 C and 60 ° C.

Table 1

It can be seen from this table that the calendar life has increased from 17.7 years at 25 ° C with a state of charge to 50% at only 2.6 years at 25 ° C with a state of charge at 100%. The calendar aging parameter is therefore a parameter that should not be neglected. Indeed the vehicle is in parking mode 95% of its time. Therefore, to improve the calendar life of the storage source, it is necessary to optimize the management of the state of charge when the battery is in storage mode. In the state of the art, for motor vehicles whose motorization makes full or partial use of a source of electrical energy storage, there is no management of the state of charge of this source so as to optimize its operation according to the need for use of the vehicle. In particular there is no management of the state of charge of the battery when the vehicle is in parking mode, in the phase of non-use. Generally, when the battery is connected to the network or to a fast charging terminal, this source is charged at full load, that is to say at 100% when the charging time is sufficient immediately, even if the vehicle does not have a charge. is not used immediately after the end of charge. Such use of the battery, in accordance with the data shown in Table 1, rapidly degrades the performance of the source of storage. According to Table 1, whatever the storage temperature, the calendar lifetime is divided by a factor of the order of 7, if the state of storage load from 50% to 100%.

The present invention therefore aims at providing a device and a battery management method for overcoming the technical disadvantages described above, to improve the life of a battery according to the different profiles of the vehicle, while allowing to size at most just the battery, depending on the specifications of the vehicle, to minimize the impact of its manufacturing cost. For this, the principle of the invention is to fully charge the electrochemical storage source but by programming its load so that it reaches the high load states just before its use so that it remains in the lowest charge states as long as possible in storage mode. The term "battery or storage source in storage mode" when the vehicle is in parking mode. In this way, the life of the battery is improved.

Of course, it is also necessary to ensure the lowest possible storage or use temperature by having an effective ventilation or air conditioning system. For this purpose, the invention therefore relates to a charging management system of an electric power storage battery power supply of an electric or hybrid power train of a vehicle. According to the invention, it comprises:

a data interface, an electronic management computer for the battery for charging the battery, this computer being connected in parallel with the battery and with means for charging the battery,

a vehicle supervisor connecting the data interface to the electronic management computer of the battery, via an Intelligent Service Enclosure (BSI),

this electronic battery management calculator comprising means for receiving information transmitted from the data interface via the vehicle supervisor and the intelligent service box BSI, information processing means for determining a duration of immobilisation of the vehicle from this information and a duration of full charge of the battery from the initial state of charge of the battery and means for programming charging instructions of the battery according to the duration of immobilization with respect to the charging time for the battery to reach the highest state of charge just before use so that it remains in a low or low state of charge for as long as possible in storage.

Thus, the management system according to the invention makes it possible to ensure that the battery in storage mode remains in a state of charge that is as low as possible for as long as possible, so that the system of the invention makes it possible to program the charge of the battery at a sufficient or full charge level for the use of the vehicle only before use, without automatically recharging the battery 100% immediately after use and leaving the battery in storage mode in a high state of charge, which would damage the battery and greatly reduces its service life.

According to one embodiment of the invention, the data interface comprises means for displaying data concerning, among other things, the state of charge of the battery before charging and at the end of charging, and means of data acquisition. In general, these data input means comprise a keypad, a remote control, or a voice recognition system.

According to one embodiment of the invention, the electronic management computer of the battery comprises an internal memory in which is recorded an abacus giving the charging time as a function of the initial state of charge of the battery.

According to one embodiment, said recharging means are constituted by a charging station and an onboard charger on board the vehicle. In addition, the system includes a clock, this clock being integrated in the electronic management computer of the battery or in the supervisor.

The invention also relates to a method of managing the state of charge of a battery implementing the charging system as defined above. According to the invention, it comprises the following steps when the driver wishes to program the charging instructions of the battery in storage mode before the next use of the vehicle:

the state of charge of the battery is measured so as to know its remaining capacity,

the date and time of the next use corresponding to the instant t _f are entered,

this information is transmitted by the vehicle supervisor to the electronic management computer of the battery which determines the duration of immobilization of the vehicle and the complete charging time of the battery;

- depending on the length of time the vehicle has been idle in relation to the duration of the total charge, the computer schedules battery charging instructions so that it reaches the highest state of charge just prior to its use; the instant t _f so that it remains in a low state of charge or as low as possible in storage.

Advantageously, the management method comprises an additional step in which:

the temperature T _m is measured within the battery

- comparing the value of the temperature measured at a temperature value T _C harge allowing charging without damaging the battery prestored in the internal memory of the computer,

when the measured value T _m is greater than the pre-recorded value T _C harge, the electronic management computer of the battery recalculates the immobilization time of the vehicle which is the difference between the immobilization time of the vehicle calculated from the information returned by the driver and the time required for the temperature in the battery reaches the level allowing charging without damaging the battery.

According to an embodiment of the method of the invention, when the computer determines that the duration of immobilization is greater than the duration of the load, the charging instructions consist in completely delaying the charge of the battery in the time of charging. so that it starts only at a time ti subsequent to t ₀ and ends at the instant t _f , the difference between the two instants t _f -ti corresponding to the charge duration of the battery determined by the computer. According to another embodiment of the method of the invention, when the computer determines that the duration of immobilization is greater than the duration of the load, the charging instructions consist in defining at least four phases of charging the battery so that it starts charging at time t ₀ corresponding to the initial moment of the immobilization phase of the vehicle and then reaches in state of charge level increments the highest state of charge (100 %) just before the instant t _f corresponding to the use of the vehicle.

Preferably, the instructions comprise four charging phases which are defined as follows:

- phase 1: the load starts at t ₀ , when the user has entered the date and time in the interface and ends when the state of charge of the battery reaches a predefined SOC1 state of charge ;

phase 2: the battery is kept idle at SOC1 for a duration t ₂ -ti,

phase 3: the charge starts at t ₂ and ends when the battery voltage reaches a value Uc at time t ₃ ,

-phase 4: the constant voltage charge Uc ends as soon as one of the two criteria is reached: - either when the intensity which decreases during this phase reaches the cutoff threshold If,

or when the duration of this phase 4 reaches a predetermined duration Δt, Δt being defined so that the charge ends at time t ₄ , t ₄ may be less than or equal to the instant t _f indicated by the driver.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given for illustrative purposes only but in no way limitative of the invention:

- Figurel schematically shows a charging management system of a battery according to the invention;

FIG. 2 represents a current and voltage profile of a battery charge as a function of time in the case of conventional battery charging management;

Figure 3.A shows the profile of the state of charge of a battery and the profile of the corresponding charging current as a function of time. of a charged battery according to a first embodiment of the invention, Figure 3B illustrating the profile of the voltage and the current profile as a function of time corresponding to the charging phase of the battery, - Figure 4A shows the profile of the state of charge of a battery and the profile of the corresponding charging current as a function of the time of a charged battery according to a second embodiment of the invention, FIG. 4B illustrating the profile of the voltage and the profile of the current depending on the time corresponding to the charging phase of the battery.

Figure 1 schematically show the architecture of a charging management system of a battery according to the invention. The battery 5 is connected here to an electric motor 8. An inverter 9 is arranged between the battery 5 and the electric motor 8 to ensure the transfer of energy between the two elements. The battery is connected on the one hand to a fast charging station 7 such as the EDF electricity network, on the other hand to an on-board charger 6 in the vehicle. This battery can be used in an electric or hybrid power train of a motor vehicle. This management system also includes a data interface

1 which can be for example a screen disposed at the level of the passenger compartment, accessible by the driver. This data interface 1 is provided with a keypad or a remote control (not shown), or a voice recognition system (not shown), allowing the driver to enter the date and time of the next use of the vehicle or the period of immobilisation of the vehicle.

To manage the charging of this battery, the system further comprises an electronic management computer battery 4 for charging the battery 5. This computer 4 is interconnected between the data interface 1 and the battery. This calculator is connected to a charging means such as a fast charging station 7 or an on-board charger 6.

This electronic charge management computer of the battery 4 comprises means for receiving the information transmitted from the data interface 1 via an intelligent servocontrol housing denoted BSI 2 and a vehicle supervisor 3, information processing means for determining a period of immobilization of the vehicle based on the information entered by the driver and a full charging time of the battery according to the initial state of charge of the battery and means for programming charging instructions of the battery 5 to reach the highest state of charge just prior to use so that it remains in a low or low state of charge for as long as possible in storage.

This battery 5 is connected either to a fast charging terminal 7 or to the network via an on-board charger 6 The various technical means constituting the electronic management computer of the battery 4 are not shown in FIG.

The electronic management computer of the battery is associated with means for measuring the voltage, current and temperature of the battery. In this way, the information such as the state of charge of the battery, the temperature thereof detected during the commissioning of this battery are also transmitted to the computer and stored in a data storage means, such as a memory internal to the calculator. This information can also be displayed continuously on the interface, they can also be displayed at the request of the driver.

When the driver enters the downtime or the date and time of the next use of the vehicle to program the battery charging instructions, this information is transmitted via the BSI 2 and the vehicle supervisor 3 to the vehicle. the calculator 4. The calculator 4 determines the time that separates the moment of the next use from the moment when the information concerning the date and the time is entered at the interface by the driver. Information such as the initial state of charge of the battery, the capacity of the battery, the current levels available by the on-board charger or the fast charging station which are stored in the internal memory of the computer then allow the battery of evaluate the full charging time of the battery.

To refine the estimation of the charge duration, it is possible to ask the computer of the electronic management of the battery 4 to determine the state of health of the battery at any moment of its lifetime in order to know the real capacity drums. An alternative solution is to enter into the computer 4 charts showing the charging time according to the initial state of charge of the battery depending on whether the battery is recharged by the on-board charger or by the fast charging station. Another even simpler solution is to enter a preset value increasing the charging time regardless whether the load is through the charger or the fast charging station, or two predefined values increasing the charging time, one for charging with on-board charger, the other for a charge with the fast terminal. Advantageously, the electronic management computer of the battery 4 can also receive the information concerning the temperatures measured within the battery to the computer. It is then possible to envisage a step of stabilizing the temperature within the battery before recharging it. For this, a temperature level is preset to allow charging without damaging the battery. The value of this temperature T _C harge is prerecorded in the internal memory of the computer 4. In this case, taking into account the temperature parameter, we can consider two situations of operation.

A first operating situation where the temperatures measured within the battery do not oppose an immediate recharge, in this case the load can start immediately.

A second situation can be envisaged in which the level of temperatures measured within the battery is higher than the tolerated level and therefore opposes an immediate recharge. In this case, the electronic management computer of the battery 4, as soon as the temperatures measured within the battery have reached levels allowing charging, recalculates the remaining downtime which is the difference between the calculated downtime from the information entered by the driver and the time required for the temperature level within the battery to reach T _C harge- The calculator then estimates if the remaining immobilization time thus updated is greater than the duration of the load complete. If so, the electronic management computer of the battery 4 then makes the decision to completely defer the load or certain phases of the load and determines the time parameters of the modified load profile. The computer 4 then schedules charging instructions of the battery so that it reaches the highest state of charge just before its use which corresponds to the instant t _f so that it remains in a low state of charge or as low as possible in storage, when the vehicle is not in use. The principle of this program is to modify the charging time profile of the conventional battery, to adapt it according to the driver's need for use. These instructions are then sent by the computer as commands to the recharging means 6, 7 to control them. Figure 2 illustrates an example of IU load time profile of a lithium battery, without charging strategy to optimize the calendar life. More precisely, FIG. 2 represents a first curve of the intensity of the charging current I (t) and a second curve of voltage U (t) between two times t ₀ and t _f . The initial moment t ₀ corresponds to the instant when the battery is connected to the network via the on-board charger 6 or to a fast charging terminal by the driver. There is a first constant current charging phase 11 which starts immediately at t ₀ until the instant t ₂ , corresponding to a voltage value Uc, followed by a second phase at constant voltage Uc during which the current decreases to an intensity of If. Generally there are two end-of-charge criteria: either when the intensity which decreases during this second phase reaches the predefined value If or when the duration of this second constant-voltage phase Uc reaches the predetermined duration Δt corresponding to t _f -1 ₂ . The duration It is clear from this charging time profile that the charge is not delayed but starts as soon as the vehicle is connected to the network or to the fast charging station and the battery is then continuously charged. As a result, the battery remains 100% charged well before the next use and will remain in this state for the duration of the immobilization of the vehicle. Such use of the battery, in accordance with the data shown in Table 1, rapidly degrades battery performance and shortens battery life.

Figures 3.A and 3B illustrate the charging time profile of a battery according to a first embodiment of the invention. The computer programs load setpoints so that it is completely different in the time the charge so that it starts only at time ti and ends at t _f corresponding to the date and time programmed by the driver. This time ti is determined by knowing the duration of the load and the total downtime of the vehicle. It is assumed here that the battery is completely discharged and that it is in a state of charge SOC = 0% before charging.

In these figures 3A and 3B, three phases are distinguished:

Phase 1: the battery is kept at rest at its rest voltage U less than Uc, the charge state level SOC being equal to 0% here in this load example for a duration ti-1 ₀ ,

Phase 2: phase 2 starts at instant t1 where it is charged at constant current 11 and ends when the voltage of the battery reaches the value Uc,

- Phase 3: phase 3 constant voltage Uc ends at t _f , corresponding to the moment entered by the driver, the charging time being equal to the difference between t _f and ti.

Thus, by implementing the management system of the invention, the battery does not remain charged unnecessarily to 100%, it reaches its maximum state of charge only just before the use of the vehicle. However, this load management mode does not allow the user to quickly have a minimum threshold state of charge allowing him immediate autonomy if he decides to use his vehicle before the time scheduled for load.

To overcome this drawback, it is recommended a second embodiment of the invention illustrated in Figures 4A and 4B. In this second embodiment, the computer programs the charging instructions so that the battery is charged in several phases. Unlike the embodiment described above, here the load starts at time tO, when the user has connected his vehicle and has entered the interface the date and time he wants to use his vehicle. This is to allow the battery to quickly reach a state of charge SOC1 allowing a minimum available autonomy if the user needed the vehicle earlier than expected. The level SOC1 can be a parameter predefined by the driver or by the computer. The value 50% would be a good value, since it allows an appreciable autonomy value while reducing the effects of calendar aging according to Table 1. Next the battery is idle at SOC1 and the charge resumes at t2 so that the charge ends at the time indicated by the user.

An example of charge time profiles obtained according to this second embodiment is illustrated in FIGS. 4A and 4B, there are four charging phases:

phase 2: the battery is kept idle at SOC1 for a duration t ₂ -ti,

-Phase 4: the constant-voltage charge Uc ends as soon as one of the two criteria is reached: - either when the intensity which decreases during this phase reaches the cutoff threshold l _f ,

or when the duration of this phase 4 reaches a prefixed duration Δt, Δt being defined so that the charge ends at the instant t ₄ indicated by the driver. In FIGS. 4A and 4B, this Δt corresponds to t ₄ -t ₃ . Thus t ₄ may be less than or equal to the instant t _f indicated by the driver.

It can also be expected that the charge ends a certain period before the date and time entered by the user, to ensure that the battery is indeed fully charged at the scheduled time of recovery of the vehicle. This duration can for example be one hour.

An exemplary application of the system and method for managing the charging of a battery according to the invention is described above:

A vehicle has a battery of 80 cells of nominal voltage

3.5V and 80Ah capacity (total energy 22kWh).

It is assumed that this vehicle has an average fuel consumption of

150Wh / km. The autonomy of this vehicle is 150km.

It is also assumed that the battery temperature in run mode, parking mode and charge mode is 25 ° C. In this example, the damage of the battery is compared in the case where the charging management system of the invention is used for damage when it has no charge management control.

1) Coefficient of damage to the battery when it has no charge management control:

Table 2 above illustrates, over a week, an example of the distribution of the hours spent at different battery charge states, assuming that the driver puts back in charge as soon as he arrives at his home:

Table 2

The damage coefficients at 25 ° C taking the coefficient equal to 1 corresponding to a lifetime of 17.7 years are summarized in Table 3.

Table 3

The average damage coefficient calculated from the values in Table 3 by weighting the percentage of hours spent at each state of charge slice in Table 2 is 6.15.

Thus this distribution of hours of the week according to the state of charge in the absence of the battery charging management system reduces the service life by a factor of 6.15, or 2.8 years.

2) Coefficient of damage of the battery by implementing the first embodiment of the charging management method:

In this example, it is assumed that the driver has chosen to use the first embodiment of the recharge management method consisting of totally deferring the recharge over time.

Table 4 above shows, over one week, the distribution of the hours spent at the different states of charge of the battery:

Table 4

The average damage coefficient calculated from the values in Table 4 by weighting the percentage of hours spent on each state of charge is 4.90: 0.12 ^* 6.8 + 0.39 ^* 5 , 5 + 0.41 ^* 4.1 + 0.08 * 3.2 = 4.90 (the coefficient 1 corresponding to a lifetime of 17,7ans).

Thus the gain brought by using the appropriate battery charging management system compared to the conventional charging mode in which the battery is automatically charged to 100% after use over the battery life is 6.15 / 4 , 90 = 1, 25 or 25% gain in life.

In the example above, the temperature is set at 25 ° C. It can be noticed that whatever the state of charge, the damage due to the temperature is the same for a battery (Table 5):

Table 5

The passage from 25 ° C to 45 ° C causes a damage of 2.8 and the passage from 25 ° C to 60 ⁰ C damage close to 5.8 whatever the level of state of charge.

Therefore it can be deduced that whatever the temperature, the battery, the gain brought or the ratio between the damage without charging management strategy and the damage by applying the recharging management system of the invention will remain the even.

Thus, thanks to the battery charging management system according to the invention, the battery in storage mode is no longer in a high charge state during the immobilization period of the vehicle. The management of its refill is optimized so that it reaches the level of charge to 100% just before the use of the vehicle. This type of charging management can significantly increase the battery life. Therefore it is no longer necessary to oversize the battery while allowing the vehicle to meet the specifications for which it was designed. This also reduces the cost of manufacturing the battery.

Claims

1. Management system for recharging an electric power storage battery (5) of an electric or hybrid power train of a vehicle, characterized in that it comprises:

a data interface (1),

an electronic battery management computer (4), this computer being connected in parallel with the battery (5) and battery recharging means (6, 7), - a vehicle supervisor (3) connecting the battery data interface (1) to the electronic battery management computer (4) via an intelligent BSI servocontrol unit (2),

said electronic battery management calculator (4) comprising means for receiving information transmitted from the data interface (1) via the vehicle supervisor (3) and the BSI intelligent servocontrol unit (2), information processing means for determining a vehicle downtime from this information and a full charge time of the battery from the initial state of charge of the battery and means for programming instructions of the battery. charging the battery (6, 7) according to the downtime versus the charging time for the battery to reach the highest state of charge just prior to use so that it remains in a state of charge low or lowest charge as long as possible in storage.

2. System according to claim 1, characterized in that the data interface (1) comprises data display means, these data relating inter alia the state of charge of the battery before charging and at the end of charging and data entry means.

3. System according to claim 2, characterized in that the data input means comprise a keypad or a remote control, or a voice recognition system.

4. System according to one of claims 1 to 3, characterized in that the computer comprises an internal memory in which is recorded a abacus giving the charging time according to the initial state of charge of the battery.

5. System according to one of claims 1 to 4, characterized in that said recharging means are constituted by a charging terminal (7) and / or an on-board charger (6) for connecting the battery (5) to a network.

6. System according to one of claims 1 to 5, characterized in that it comprises a clock, this clock being integrated in the electronic management computer of the battery (4) or in the vehicle supervisor (3).

7. A method of managing the state of charge of a battery (5) implementing the recharging system defined according to one of claims 1 to 6, characterized in that it comprises the following steps when the driver wishes schedule the battery charge instructions in storage mode before the next use of the vehicle:

- the state of charge of the battery is measured to know its remaining capacity, - one enters the date and the time of the next use corresponding to the instant t _f ,

all of this information is transmitted by the vehicle supervisor (3) to the electronic battery management computer (4) which determines the immobilization time of the vehicle and the complete charging time of the battery;

according to the duration of immobilization of the vehicle with respect to the duration of the complete charge, the computer (4) schedules charging instructions of the battery so that it reaches the highest state of charge just before its use, at time t _f so that it remains in a low charge state or lowest for as long as possible in storage.

8. Management method according to claim 7, characterized in that it comprises an additional step in which:

the temperature T _m within the battery (5) is measured, the value of this measured temperature is compared with a value of temperature T _C charging allowing a recharge without damaging the prerecorded battery in the internal memory of the computer (4),

when the measured value T _m is greater than the pre-recorded value T _C harge, the electronic management computer of the battery (4) recalculates the immobilization time of the vehicle which is the difference between the immobilization time of the vehicle calculated at from the information entered by the driver and the time required for the temperature in the battery reaches the level allowing charging without damaging the battery.

9. Management method according to claim 7 or 8, characterized in that when the computer determines that the immobilization time of the vehicle is greater than the duration of the complete charge, the charging instructions consist in completely deferring the charge of the battery in time so that it starts only at time ti and ends at the date and time entered by the user t _f , the difference between the two times t _f -ti corresponding to the duration of charge of the battery determined by the calculator.

10. Management method according to claim 7, characterized in that when the immobilization time of the vehicle is greater than the total charging time, the charging instructions consist in defining at least four charging phases of the battery so that it starts the charge at time t ₀ corresponding to the initial moment of the immobilization phase of the vehicle and then reaches the highest state of charge (100%) just before the use of the vehicle in stages of state of charge level and ends at the instant t _f .

11. Management method according to claim 10, characterized in that the charging instructions comprise four charging phases which are defined as follows:

phase 1: the charge starts at t ₀ and ends when the state of charge of the battery reaches a predefined state of charge state SOC1;

phase 2: the battery is kept idle at SOC1 for a duration t ₂ -ti, phase 3: the charge starts at t ₂ and ends when the battery voltage reaches a value Uc at time t ₃ ,